The use of fiber (primarily glass fiber) reinforced plastic (“FRP”) parts is widespread in many industries, including manufacturing, marine, aerospace, transportation, or any industry demanding molded, durable high strength, parts. FRP is a standard and understood name for fiberglass parts in the field of art and includes reinforcement materials other than fiberglass. Typically these parts must be made using expensive forms or molds. What is needed in the industry is an apparatus and method for the fabrication of FRP parts without the use of forms or molds.
There are previously known methods relating to the construction and operation of computer controlled machine tools (“computer numerically controlled machines” or “CNC machines”) for metal working, painting, welding, woodworking and assembly. There are previously known radiation-initiated resins used in making prototype parts within a liquid bath (“rapid prototyping”). There is also related art referring to the application of resin (some radiation-initiated) impregnated yarns (tow) or ribbons of reinforcements to rotating mandrels of given shapes to form parts on those mandrels (“filament winding”). In addition, there are applications where radiation-initiated resin impregnated reinforcements are deposited on two- and three-dimensional mold surfaces by CNC machines. This pultrusion process pulls an FRP shape out of a die, and radiation-initiated resins are used to allow for the bending of the shape as it emerges from the die. Applicant is unaware of any work preceding that of the present invention that describes an apparatus and method enabling the use of a CNC machine to make FRP parts, without the use of forms or molds in practically any size or shape, according to a preferred embodiment of the present invention.
The apparatus and method according to a preferred embodiment of the present invention represents a more economical process to create these FRP parts. The following example provides some idea of the value of the apparatus and method.
A boat hull requires the following steps to proceed from drawing to finished product using processors according to the prior art: 1) build forms to make a ‘plug’ or mock up of the hull; 2) fair up and smooth the plug to final dimension and finish (a CNC machine is typically used for this step); 3) laminate a female mold over the plug; and 4) laminate a complete hull in the mold.
Using current technology, the probable cost for a 45 foot hull could easily exceed $500,000.00 and require 6 months to complete depending upon the degree of accuracy and finish desired.
The same hull created by the apparatus and method according to a preferred embodiment of the present invention would require the following steps: 1) operate the novel extrusion system of the present invention for a period long enough to make the desired shape; 2) smooth the surface; and 3) build up thickness on the inside of the hull.
It is probable that this work could cost less than $30,000.00 and require no more than 1 month to complete for a 45 foot boat hull, and the finished product could be reasonably expected to be as, or more, geometrically exact than the product of the prior art process. Additionally, the novel process according to an embodiment of the present invention would provide more consistently accurate results because of the elimination of steps between the CNC machine work and the finished part.
There is no process known to exist that can create a large FRP shape in space that is dimensionally accurate, and possesses structural integrity. All of the materials used to make this FRP laminate become a contributing functional part of the finished structure and are compatible with materials used in secondary operations to increase strength through build-up of thickness on the inside of the structure or for attaching components.